Findings could shed light on early conditions for life on Mars — and on Earth, too

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This false-color view of the floor of McLaughlin Crater shows sedimentary rocks that contain spectroscopic evidence for minerals formed through interaction with water. The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter recorded the image.

New photos of a huge crater on Mars suggest water may lurk in crevices under the planet's surface, hinting that life might have once lived there, and raising the possibility that it may live there still, researchers say.

Science editor Alan Boyle's blog: "Astronaut Abby" is at the controls of a social-media machine that is launching the 15-year-old from Minnesota to Kazakhstan this month for the liftoff of the International Space Station's next crew.

Future research looking into the chances of life on Mars could shed light on the origins of life on Earth, scientists added.

The discovery came from a study of images by NASA's powerful Mars Reconnaissance Orbiter that revealed new evidence of a wet underground environment on the Red Planet. The images focused on the giant McLaughlin Crater, which is about 57 miles (92 kilometers) wide and so deep that underground water appears to have flowed into the crater at some point in the distant past.

Today, the crater is bone-dry but harbors clay minerals and other evidence that liquid water filled the area in the ancient past.

"Taken together, the observations in McLaughlin Crater provide the best evidence for carbonate forming within a lake environment instead of being washed into a crater from outside," study lead author Joseph Michalski, of the Planetary Science Institute in Tucson, Ariz., and London's Natural History Museum, said in a statement.

A wet Mars underground
Space agencies have deployed many missions to Mars over the decades to explore how habitable its surface may have been or is today. However, the Martian surface has been extremely cold, arid and chemically hostile to life as we know it for most of the history of Mars.

Instead of scanning the surface of Mars for life, scientists have suggested the most viable habitat for ancient simple life may have been in Martian water hidden underground.

On Earth, microbes up to 3 miles (5 kilometers) or more underground make up perhaps half of all of the planet's living matter. Most of these organisms represent some of the most primitive kinds of microbes known, hinting that life may actually have started underground, or at least survived there during a series of devastating cosmic impacts known as the Late Heavy Bombardment that Earth and the rest of the inner solar system endured about 4.1 billion to 3.8 billion years ago.

Since Mars has less gravity — a surface gravity of a little more than one-third Earth's — its crust is less dense and more porous than that of our planet, which means that more water can leak underground, researchers said. Wherever there is liquid water on Earth, there is virtually always life, and microbes underground on Mars could be sustained by energy sources and chemical reactions similar to those that support deep-dwelling organisms on Earth.

"The deep crust has always been the most habitable place on Mars, and would be a wise place to search for evidence for organic processes in the future," Michalski told Space.com. [Search for Life on Mars: A Timeline (Gallery)]

Subterranean Mars
While researchers currently have no way to drill deep underground on the Red Planet, they can nevertheless spot hints of what subterranean Mars is like by analyzing deep rocks exhumed by erosion, asteroid impacts or materials generated by underground fluids that have welled up to the surface.

Such upwelling would first occur in deep basins like McLaughlin Crater — as the lowest points on the surface, they would be where underground water reserves would most likely get exposed.

Scientists focused on McLaughlin Crater because it is one of the deepest craters on Mars. McLaughlin is about 1.3 miles (2.2 kilometers) deep and is located in Mars' northern hemisphere.

The mineral composition of the floor of McLaughlin Crater suggests there was a lake made of upwelled groundwater there. Channels seen on the crater's eastern wall about 1,650 feet (500 meters) above its floor also hint at the former presence of a lake surface.

Michalski was actually originally trying to disprove the idea that groundwater breached the surface in many locations on Mars.

"Lo and behold, there was strong evidence for that process in this crater," he said. "Science is special because we are allowed to change our minds."

An ancient groundwater lake
The researchers estimate that a lake existed at McLaughlin Crater for an unknown duration between 3.7 billion and 4 billion years ago. "That makes the deposits as old as or older than the oldest rocks known to exist on Earth," Michalski said.

Mounds seen on the crater floor may have come from landslides or subsequent meteor impacts. These are important because they may have rapidly buried crater floor sediments.

"That is really cool because rapid burial is the scenario that is most advantageous for preservation of organic material, if any was present at that time," Michalski said.

Since life on Earth may have begun underground, learning more about any underground life that might have lived — or may still live — on Mars could shed light on the origins of life on Earth, researchers said.

Michalski noted that some people may ask, "'Why do I hear about the detection of water or possibility of life on Mars all the time?' The answer is because Mars is habitable in more ways than we ever realized for many years, and we are finding water in many forms and environments on Mars — many more than we predicted for a long time."

The ingredients for life the researchers describe, "including energy sources, would have been more available early in Mars' history, but it doesn't take too much imagination to picture a scenario in which the subsurface is habitable today," Michalski said. He cautioned, however, "that is much different from saying that life is there today."

The scientists detailed their findings online Jan. 20 in the journal Nature Geoscience.

Southern stargazing

Stars, galaxies and nebulas dot the skies over the European Southern Observatory's La Silla Paranal Observatory in Chile, in a picture released on Jan. 7. This image also shows three of the four movable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: They reveal details that would otherwise be visible only through a telescope as large as the distance between them.
(Y. Beletsky / ESO)
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A balloon's view

Cameras captured the Grandville High School RoboDawgs' balloon floating through Earth's upper atmosphere during its ascent on Dec. 28, 2013. The Grandville RoboDawgs’ first winter balloon launch reached an estimated altitude of 130,000 feet, or about 25 miles, according to coaches Mike Evele and Doug Hepfer. It skyrocketed past the team’s previous 100,000-feet record set in June. The RoboDawgs started with just one robotics team in 1998, but they've grown to support more than 30 teams at public schools in Grandville, Mich.
(Kyle Moroney / AP)
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Spacemen at work

Russian cosmonauts Oleg Kotov, right, and Sergey Ryazanskiy perform maintenance on the International Space Station on Jan. 27. During the six-hour, eight-minute spacewalk, Kotov and Ryazanskiy completed the installation of a pair of high-fidelity cameras that experienced connectivity issues during a Dec. 27 spacewalk. The cosmonauts also retrieved scientific gear outside the station's Russian segment.
(NASA)
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Special delivery

The International Space Station's Canadian-built robotic arm moves toward Orbital Sciences Corp.'s Cygnus autonomous cargo craft as it approaches the station for a Jan. 12 delivery. The mountains below are the southwestern Alps.
(NASA)
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Accidental art

A piece of art? A time-lapse photo? A flickering light show? At first glance, this image looks nothing like the images we're used to seeing from the Hubble Space Telescope. But it's a genuine Hubble frame that was released on Jan. 27. Hubble's team suspects that the telescope's Fine Guidance System locked onto a bad guide star, potentially a double star or binary. This caused an error in the tracking system, resulting in a remarkable picture of brightly colored stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288.
(NASA / ESA)
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Supersonic test flight

A camera looking back over Virgin Galactic's SpaceShipTwo's fuselage shows the rocket burn with a Mojave Desert vista in the background during a test flight of the rocket plane on Jan. 10. Cameras were mounted on the exterior of SpaceShipTwo as well as its carrier airplane, WhiteKnightTwo, to monitor the rocket engine's performance. The test was aimed at setting the stage for honest-to-goodness flights into outer space later this year, and eventual commercial space tours.

Red lagoon

The VLT Survey Telescope at the European Southern Observatory's Paranal Observatory in Chile captured this richly detailed new image of the Lagoon Nebula, released on Jan. 22. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of 11 public surveys of the sky now in progress using ESO telescopes.
(ESO/VPHAS team)
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Fire on the mountain

This image provided by NASA shows a satellite view of smoke from the Colby Fire, taken by the Multi-angle Imaging SpectroRadiometer aboard NASA's Terra spacecraft as it passed over Southern California on Jan. 16. The fire burned more than 1,863 acres and forced the evacuation of 3,700 people.
(NASA via AP)
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Where stars are born

An image captured by NASA's Spitzer Space Telescope shows the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This false-color infrared view, released on Jan. 15, spans about 40 light-years across the region. The brightest portion of the nebula is centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But Spitzer also can detect stars still in the process of formation, seen here in red hues.
(NASA / JPL-Caltech)
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A long, long time ago...

This long-exposure picture from the Hubble Space Telescope, released Jan. 8, is the deepest image ever made of any cluster of galaxies. The cluster known as Abell 2744 appears in the foreground. It contains several hundred galaxies as they looked 3.5 billion years ago. Abell 2744 acts as a gravitational lens to warp space, brightening and magnifying images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang.
(NASA / NASA via AFP - Getty Images)
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Frosty halo

Sun dogs are bright spots that appear in the sky around the sun when light is refracted through ice crystals in the atmosphere. These sun dogs appeared on Jan. 5 amid brutally cold temperatures along Highway 83, north of Bismarck, N.D. The temperature was about 22 degrees below zero Fahrenheit, with a 50-below-zero wind chill.